This Instructable demonstrates how to modify a standard Icom IC-T7H hand-held dual-band radio transceiver to both receive and transmit on a wider range of frequencies.

Original:

2 Meter: 144.0-148.0 MHz
70 Centimeter: 420.0-450.0 MHz.

Modified:

2 Meter: 118.0 - 174.0 MHz
70 Centimeter: 400.0 - 470.0 MHz.

Hopefully this will be the first of many ham radio related Instructables I will post.

Side note:

This modification should only be made in preparation for emergency situations where communications out of regular ham bands are necessary, at no other time should an amateur radio operator transmit on frequencies outside of ham bands.

Step 1: Step 1, Disassembly

There are 10 screws that need to be removed to gain access to the internal control circuitry.

Four above the battery compartment

Two at the top of the battery compartment

And two at the bottom of the battery compartment

Remove these screws and set them aside carefully so they don't get lost or knocked around and then proceed to step two.

Step 2: Opening the Tranciever and Identifying D15

After removing the ten screws the radio should separate fairly easily into 3 parts,

The top "controller unit"

The back-plane "logic unit"

And the battery compartment cover which is just a piece of metal.

Next take a second to locate D15, a 3 pin diode in the lower right of the back-plane logic unit.

After locating the diode and checking out the rest of the awesome circuitry head to step three.

Step 3: Remove D15 and Reassemble

At this point you need to remove D15

There are many ways to do this and I'm no pro myself but I suggest desoldering the single pin on the bottom side of D15 and then simply using a toothpick or small instrument to lever it out.

Be very careful not to damage any other components in the process and use low heat on your soldering iron if you use one.

After you have removed the Diode reassemble the radio using the screws removed earlier and rest easy knowing in an emergency your radio can now reach out to a much broader audience.

Modifications such as this simply make your radio a more versatile tool, but keep in mind, like any modifications to RF equipment it is likely the FCC would frown on this unless used for emergency purposes by a licensed ham operator.

Until next time,

BlastwaveLabs

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33 Comments

wd4lwq

2 years ago

I would be wary of using my equipment out of band in an emergency, unless I had tried in band FIRST and had no luck.
Even then, unless I was in marine frequencies or maybe gmrs I wouldn't bet my life on it. Most of the public safety has gone to 700-900 mhz, and would be inaccessible, even if they were, they are pretty hostile to outsiders, as too many have used baofengs to cause havoc.

bkhosman

5 years ago

I have safely completed this modification and I have to say, WOW! it works great! I had to buy a new Soldering iron to do the mod because the bit I had was not small enough to remove the component without destroying other components. I was able to modify three radios total. Thank you for the information and remember to abide by the rules of the FCC.

erick.galdino

8 years ago

hi friends..I bu aic-t7h mod...but this stop to send tx when a push the ptt. It receive normal..But dont transmit. When I push the ptt, I see that send sinal but not work microfone.

chopz82

8 years ago

how do i get a communicaty code coz i work on the doors in the uk in lancashire

jackdog

8 years ago on Introduction

I have a baoefeng uv-5re...is there a way to modify it to receive cb radio frequencies? Thanks

LinT1

8 years ago on Introduction

Established in 1989, as one of the core
and leading manufactures of wireless 2 way radios.

BFDX is the first group of wireless communication equipment
research and development enterprise to integrate the hardware, RF, and software
in China.

tracy@bfdx.com

www.bfdx.com

camogreen

10 years ago on Introduction

This is legal in an emergency. Doesn't mean you may not need a lawyer but what jury will convict if you helped save life? Handsome boy BTW.

Mike

JokerSmoker

8 years ago on Introduction

Will this work on a Baofeng UV-5R? Would it be pretty much the same diode? I am getting 2 in a week for my friend and I. Also, someone said you wouldn't be able to hear people but they could hear you. Is that true? One last question following that. Would it work in close range to a network? E.g. our High schools frequency for maintenance is listed on a database, so if we were at school could we listen to them? or still would they only hear us?

welder guy

13 years ago on Introduction

if i do this i would be able to rx and tx on 160 to 161 MHz right. evn though it ould be illegal unless in an emergency i would still be able to right? another thing the pin you have to desolder is the one on the left side of the diode right? please reply' 73's KC2VDM